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| United States Patent |
5,618,901
|
|
Smierciak
, et al.
|
April 8, 1997
|
Process for making a high nitrile multipolymer prepared from
acrylonitrile and olefinically unsaturated monomers
Abstract
A homogeneous, high nitrile melt processable acrylonitrile olefinically
unsaturated multipolymer and a process for making the multipolymer,
comprising polymerizing a mixture of acrylonitrile monomer and one or more
olefinically unsaturated monomers, in which the rate of addition of the
multimonomer mixture is set by the rate of polymerization so that the
concentration of unreacted acrylonitrile monomers and unreacted
olefinically unsaturated monomer(s) is low and the polymerization process
is in a monomer starved condition.
| Inventors:
|
Smierciak; Richard C. (Aurora, OH);
Wardlow, Jr.; Eddie (Shaker Hts., OH);
Ball; Lawrence E. (Akron, OH)
|
| Assignee:
|
The Standard Oil Company (Cleveland, OH)
|
| Appl. No.:
|
387303 |
| Filed:
|
February 27, 1995 |
| Current U.S. Class: |
526/342 |
| Intern'l Class: |
C08F 220/48 |
| Field of Search: |
526/342
|
References Cited
U.S. Patent Documents
| 2692875 | Oct., 1954 | Weinstock, Jr. et al.
| |
| 3565876 | Feb., 1971 | Ball et al.
| |
| 4577008 | Mar., 1986 | Benton et al. | 526/342.
|
| 4719150 | Jan., 1988 | Huber et al. | 526/342.
|
| 5106925 | Apr., 1992 | Curatolo et al. | 526/342.
|
| Foreign Patent Documents |
| 1147040 | Apr., 1963 | DE | 526/342.
|
| 46-3071 | Jan., 1971 | JP | 526/342.
|
| 49-67987 | Jul., 1974 | JP | 526/342.
|
| 1260016 | Oct., 1989 | JP | 526/342.
|
| 823345 | Nov., 1959 | GB | 526/342.
|
Primary Examiner: Schofer; Joseph L.
Assistant Examiner: Sarofim; N.
Attorney, Agent or Firm: Untener; David J., Esposito; Michael F., Gilbert; Teresan W.
Parent Case Text
RELATED APPLICATION
This patent application is a continuation-in-part to patent application
entitled "A PROCESS FOR MAKING A POLYMER OF ACRYLONITRILE,
METHACRYLONITRILE AND OLEFINICALLY UNSATURATED MONOMERS", U.S. Ser. No.
08/150,515 and filed on Nov. 10, 1993 abandoned. It is understood that the
term multipolymer herein includes copolymers, terpolymers and
multipolymers throughout the specification.
Claims
What is claimed:
1. A process for polymerizing an acrylonitrile monomer and one or more
olefinically unsaturated monomers to make an acrylonitrile olefinically
unsaturated multipolymer, said process comprising the steps of:
heating an initial multimonomer mixture comprising acrylonitrile monomer
and one or more olefinically unsaturated monomer, under an inert
atmosphere, in the range of about 30.degree. C. to about 120.degree. C.;
adding an initiator to the initial multimonomer mixture to start a
polymerization reaction;
adding a multimonomer feed mixture comprising acrylonitrile monomer and
olefinically unsaturated monomer(s) to the polymerization mixture wherein
the multimonomer feed mixture contains about 50% by weight to about 95% by
weight acrylonitrile monomer and about 5% by weight to about 50% by weight
olefinically unsaturated monomer(s), wherein the multimonomer feed mixture
has a fixed and constant molar ratio of acrylonitrile monomer to
olefinically unsaturated monomer(s); and wherein the rate of addition of
the multimonomer feed mixture is less than or equal to the rate of
polymerization.
2. The process of claim 1 wherein a molecular weight modifier is added to
the initial multimonomer mixture, to the multimonomer feed mixture or to
both mixtures in the range of about 0% by weight to about 5% by weight of
total multimonomer mixture and is selected from the group consisting of
mercaptans, alcohols, halogen compounds and combinations thereof.
3. The process of claim 2 wherein the molecular weight modifier is a
mono-mercaptan, a multifunctional mercaptan or combinations thereof and
further wherein the mercaptan is selected from the group consisting of
C.sub.5 to C.sub.18 alkyl mercaptans which are straight chained, branched,
substituted, unsubstituted and combinations thereof.
4. The process of claim 3 wherein the mercaptan is selected from the group
consisting of t-dodecyl mercaptan, n-octyl mercaptan, d-limonene
dimercaptan and combinations thereof.
5. The process of claim 1 wherein the initial multimonomer mixture is
heated from about 50.degree. C. to about 80.degree. C.
6. The process of claim 1 wherein the initiator is added to the initial
multimonomer mixture in the range of 0.01% by weight to about 5% by weight
of total multimonomer mixture and is selected from the group consisting of
azo compounds, peroxides, hydroperoxides, alkyl peroxides,
peroxydicarbonates, peroxyesters, dialkyl peroxides, persulfates,
perphosphates and combinations thereof.
7. The process of claim 1 further comprising the step of adding an
initiator continuously to the polymerization reaction media and wherein
the initiator is added to the polymerization reaction media at about 0.01%
by weight to about 5% by weight of total multimonomer mixture and is
further selected from the group consisting of azo compounds, peroxides,
hydroperoxides, alkyl peroxides, peroxydicarbonates, peroxyesters, dialkyl
peroxides, persulfates, perphosphates and combinations thereof.
8. The process of claim 1 wherein the combined weight of unreacted
acrylonitrile monomer and unreacted olefinically unsaturated monomer
present in the polymerizing mixture, at any time, is not greater than
about 15% by weight of the polymerizing mixture.
9. The process of claim 1 wherein the combined weight of unreacted
acrylonitrile monomer and unreacted olefinically unsaturated monomer
present in the polymerizing mixture, at any time, is not greater than
about 10% by weight of the polymerizing mixture.
10. The process of claim 1 wherein the combined weight of unreacted
acrylonitrile monomer and unreacted olefinically unsaturated monomer
present in the polymerizing mixture, at any time, is not greater than
about 5% by weight of the polymerizing mixture.
11. The process of claim 1 wherein said process is carried out as an
emulsion, a solution, a suspension or in continuous addition bulk.
12. The process of claim 1 wherein the olefinically unsaturated monomer is
selected from the group consisting of acrylates, methacrylates,
acrylamides, methacrylamides, acrylamide derivatives, methacrylamide
derivatives, vinyl esters, vinyl ethers, vinylamides, vinyl ketones,
styrenes, halogen containing monomers, ionic monomers, acid containing
monomers, base containing monomers, olefins and combinations thereof.
13. The process of claim 12 wherein the olefinically unsaturated monomer is
selected from the group consisting of methyl acrylate, ethyl acrylate,
methyl methacrylate, vinyl acetate, styrene, .alpha.-methyl styrene,
indene, vinyl bromide, vinylidene chloride, sodium vinyl sulfonate, sodium
styrene sulfonate, sodium methallyl sulfonate, itaconic acid, styrene
sulfonic acid, vinyl sulfonic acid, isobutylene, ethylene, propylene and
combinations thereof.
14. The process of claim 12 wherein the olefinically unsaturated monomer is
selected from the group consisting of .alpha.-methyl styrene, methyl
acrylate, methyl methacrylate, styrene, vinyl acetate and combinations
thereof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a homogeneous acrylonitrile olefinically
unsaturated multipolymer and a process to make the same. This multipolymer
has molecularly uniform monomer sequences throughout the multipolymer, has
a high nitrile polymer content and is melt processable. More specifically,
the invention relates to a monomer starved process for producing an
acrylonitrile olefinically unsaturated multipolymer in which the
polymerization rate exceeds or equals the addition rate of the
multimonomers of acrylonitrile monomers and olefinically unsaturated
monomer(s).
2. Description of the Prior Art
Acrylic polymers are high nitrile polymers which are desirable in the
production of fibrous textiles, films, molded objects, packaging
applications and the like. High nitrile polymers have excellent physical,
thermal and mechanical properties such as barrier properties, chemical
resistance, rigidity, heat resistance, UV resistance, moisture retention
and bacteria resistance.
However, acrylic polymers and multipolymers having long repeating sequences
of acrylonitrile monomer units are known to degrade when heated and
processed by commercial methods. The long sequences of nitrile units make
the acrylic high nitrile polymers non-processable without the use of
solvent.
Thermoplastic nitrile barrier polymer resins are known in the art and have
been described in U.S. Pat. Nos. 3,426,102 and 3,586,737. These nitrile
polymers are known to have desirable barrier properties and chemical
resistance. However, these thermoplastic nitrile polymers while melt
processable are difficult to process.
U.S. Pat. No. 5,106,925 discloses a thermoplastic nitrile polymer. However,
the process to produce the nitrile polymer is based on tracking the
polymer conversion and adding the reactants in the same mount as they are
removed and converted to polymer. This process must make proper
adjustments in rates and quantities throughout the polymerization process.
It is desirable to produce thermoplastic high nitrile multipolymers by a
process in which the nitrile monomer units are uniformly sequenced
throughout the chain. It is advantageous to produce a homogeneous
acrylonitrile olefinically unsaturated multipolymer with improved
thermoplastic properties and a high nitrile content which multipolymers
are melt processable in the absence of a solvent. It is an object of the
invention to make a nitrile polymer chain with uniformly sequenced and
short sequences of the nitrile monomer in a process that has a fixed
monomer feed ratio.
SUMMARY OF THE INVENTION
The present invention provides a new melt-processable multipolymer
comprising about 50% to about 95% polymerized acrylonitrile and about 5%
to about 50% polymerized olefinically unsaturated monomer which is
melt-processable and contains relatively uniform distribution of monomers
in the multipolymer chain.
The present invention provides a new and an improved process for producing
an acrylonitrile olefinically unsaturated multipolymer with improved
thermal stability, excellent mechanical and excellent physical properties.
The process comprises polymerizing an acrylonitrile monomer and one or
more olefinically unsaturated monomers in which the rate of addition of
the acrylonitrile monomer and the olefinically unsaturated monomer(s) is
set to be equal to or less than the rate of polymerization to maintain a
monomer starved process. Further, the weight of unreacted acrylonitrile
monomer and unreacted olefinically unsaturated monomer(s) is not greater
than 15% of the weight of the polymerizing mixture. Further, the molar
ratio of acrylonitrile monomer and olefinicaily unsaturated monomer(s) is
fixed and constant for the multimonomer feed throughout the polymerization
process and the multipolymer product ratio is similar to the multimonomer
feed ratio.
The present invention provides in particular, a process for polymerizing an
acrylonitrile monomer and one or more olefinically unsaturated monomers to
make an acrylonitrile olefinically unsaturated multipolymer, said process
comprising the steps of:
heating an initial multimonomer mixture comprising acrylonitrile monomer
and one or more olefinically unsaturated monomer, under an inert
atmosphere, in the temperature range of about 30.degree. C. to about
120.degree. C.;
adding an initiator to the initial multimonomer mixture to start a
polymerization reaction;
adding a multimonomer feed mixture comprising acrylonitrile monomer and
olefinically unsaturated monomer(s) to the polymerization mixture wherein
the multimonomer feed mixture contains about 50% by weight to about 95% by
weight acrylonitrile monomer and about 5% by weight to about 50% by weight
olefinically unsaturated monomer(s), wherein the multimonomer feed mixture
has a fixed and constant molar ratio of acrylonitrile monomer to
olefinically unsaturated monomer(s), wherein the rate of addition of the
multimonomer feed mixture is less than or equal to the rate of
polymerization resulting in a homogeneous acrylonitrile olefinically
unsaturated multipolymer product; wherein the acrylonitrile olefinically
unsaturated multipolymer produced is about 50% by weight to about 95% by
weight polymerized acrylonitrile monomer and about 5% by weight to about
50% by weight polymerized olefinically unsaturated monomer(s) and wherein
said multipolymer is thermally stable and melt processable without the use
of solvents.
The process of the present invention produces a thermoplastic homogeneous
acrylonitrile olefinically unsaturated multipolymer in which short
sequences of acrylonitrile monomer and short sequences of olefinically
unsaturated monomer(s) are interdispersed randomly throughout the
polymerized chain resulting in a thermally stable melt processable
multipolymer with improved characteristics. The acrylonitrile olefinically
unsaturated multipolymer is melt processable in the absence of solvent or
plasticizing agent to produce high nitrile products.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a homogeneous, melt processable high
nitrile multipolymer prepared from polymerizing an acrylonitrile monomer
and one or more olefinically unsaturated monomers and the process to
produce the multipolymer.
The new and improved process for producing a thermally stable, melt
processable multipolymer from acrylonitrile monomer and olefinically
unsaturated monomer(s) is accomplished by controlling the rate of addition
of the acrylonitrile monomer and the olefinically unsaturated monomer(s)
relative to the rate of polymerization. The process of the invention is a
monomer starved process in which the polymerization reaction rate exceeds
or equals the multimonomer feed mixture addition rate. The low
concentration of the unreacted multimonomers during the polymerization
step generates a monomer starved condition which prevents long sequences
of acrylonitrile monomer in the multipolymer. The multipolymer contains
short sequences of polymerized olefinicaily unsaturated monomer
interdispersed between short sequences of polymerized acrylonitrile
monomer for example, AN-AN-X-AN-AN-X-X- AN-X -X (AN=acrylonitrile unit and
X=olefinically unsaturated unit), allowing for melt processability of the
high nitrile thermoplastic acrylonitrile olefinically unsaturated
multipolymer in the absence of solvent.
The rate of addition of the acrylonitrile monomer and the olefinically
unsaturated monomer(s) is continuous throughout the polymerization
reaction. The molar ratio of the multimonomer feed mixture of
acrylonitrile monomer and olefinically unsaturated monomer(s) is constant
and fixed throughout the process. The process produces a homogeneous
composition of a thermoplastic high nitrile multipolymer similar to the
molar ratio of the incoming multimonomer feed mixture. The multipolymer
material made in the early part of the process is substantially similar to
the multipolymer material made at the end of the process, meaning there is
no major shift either in composition or sequencing of the multipolymers,
resulting in a homogeneous multipolymer product.
The thermoplastic high nitrile multipolymer that is produced by the process
of the instant invention comprises about 50% to about 95%, preferably
about 65% to about 90% and most preferably about 70% to about 90% of
polymerized acrylonitrile monomer, and about 5% to about 50%, preferably
about 10% to about 35% and most preferably about 10% to about 30% of
polymerized olefinically unsaturated monomer(s).
The olefinically unsaturated monomer employed in the present invention is
one or more of any olefinically unsaturated monomer with a C=C double bond
polymerizable with an acrylonitrile monomer. The olefinically unsaturated
monomer employed in the multimonomer mixture can be a single polymerizable
monomer resulting in a copolymer or a combination of polymerizable
monomers resulting in a terpolymer or a multipolymer.
The olefinically unsaturated monomer generally includes but is not limited
to acrylates, methacrylates, acrylamide and its derivatives,
methacrylamide and its derivatives, vinyl esters, vinyl ethers, vinyl
aides, vinyl ketones, styrenes, halogen containing monomers, ionic
monomers, acid containing monomers, base containing monomers, olefins and
the like.
The acrylates include but are not limited to C.sub.1 to C.sub.12 alkyl,
aryl and cyclic acrylates such as methyl acrylate, ethyl acrylate, phenyl
acrylate, butyl acrylate and isobornyl acrylate, 2-ethylhexyl acrylate and
functional derivatives of the acrylates such as 2-hydroxyethyl acrylate,
2-chloroethyl acrylate and the like. The preferred acrylates are methyl
acrylate and ethyl acrylate.
The methacrylates include but are not limited to C.sub.1 to C.sub.12 alkyl,
aryl and cyclic methacrylates such as methyl methacrylate, ethyl
methacrylate, phenyl methacrylate, butyl methacrylate, isobornyl
methacrylate, 2-ethylhexyl methacrylate and functional derivatives of the
methacrylates such as 2-hydroxyethyl methacrylate, 2-chloroethyl
methacrylate and the like. The preferred methacrylate is methyl
methacrylate.
The acrylamides and methacrylamides and each of their N-substituted alkyl
and aryl derivatives include but are not limited to acrylamide,
methacrylamide, N-methyl acrylamide, N,N-dimethyl acrylamide and the like.
The vinyl esters include but are not limited to vinyl acetate, vinyl
propionate, vinyl butyrate and the like. The preferred vinyl ester is
vinyl acetate.
The vinyl ethers include but are not limited to C.sub.1 to C.sub.8 vinyl
ethers such as ethyl vinyl ether, butyl vinyl ether and the like.
The vinyl amides include but are not limited to vinyl pyrrolidone and the
like.
The vinyl ketones include but are not limited to C.sub.1 to C.sub.8 vinyl
ketones such as ethyl vinyl ketone, butyl vinyl ketone and the like.
The styrenes include but are not limited to methylstyrenes, styrene,
indene, a styrene of the formula:
##STR1##
wherein each of A, B, C, and D is independently selected from hydrogen (H)
and C.sub.1 to C.sub.4 alkyl groups, substituted styrenes,
multiply-substituted styrenes and the like.
The halogen containing monomers include but are not limited to vinyl
chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene
bromide, vinylidene fluoride, halogen substituted propylene monomers and
the like. The preferred halogen containing monomers are vinyl bromide and
vinylidene chloride.
The ionic monomers include but are not limited to sodium vinyl sulfonate,
sodium styrene sulfonate, sodium methallyl sulfonate, sodium acrylate,
sodium methacrylate and the like. The preferred ionic monomers are sodium
vinyl sulfonate, sodium styrene sulfonate and sodium methallyl sulfonate.
The acid containing monomers include but are not limited to acrylic acid,
methacrylic acid, vinyl sulfonic acid, itaconic acid, styrene sulfonic
acid and the like. The preferred acid containing monomers are itaconic
acid, styrene sulfonic acid and vinyl sulfonic acid.
The base containing monomers include but are not limited to vinyl pyridine,
2-aminoethyl-N-acrylamide, 3-aminopropyl-N-acrylamide, 2-aminoethyl
acrylate, 2-aminoethyl methacrylate and the like.
The olefins include but are not limited to isoprene, butadiene, C.sub.2 to
C.sub.8 straight chained and branched alpha-olefins such as propylene,
ethylene, isobutylene, diisobutylene, 1-butene and the like. The preferred
olefins are isobutylene, ethylene and propylene.
The olefinically unsaturated monomer does not include nitrile monomers such
as methacrylonitrile. The acrylonitrile olefinicaily unsaturated
multipolymer does not contain methacrylonitrile.
The choice of olefinically unsaturated monomer or combination of monomers
depends on the properties desired to impart to the resulting high nitrile
multipolymer and its end use. For instance, polymerizing monomers of
acrylonitrile and styrene and/or indene results in a high nitrile
multipolymer and its end products with improved heat distortion
temperature and glass transition temperature. Polymerizing monomers of
acrylonitrile and isobutylene improves the flexibility of the high nitrile
multipolymer and its end products. Polymerizing monomers of acrylonitrile
and acrylates and/or methacrylates improves the processability of the high
nitrile multipolymer and its end products. Polymerizing acid-containing
monomers, base containing monomers and/or hydroxyl group containing
monomers with an acrylonitrile monomer provides useful dye sites which
enhance the colorability of the resulting high nitrile multipolymer.
Polymerizing monomers of acrylonitrile and a halogen containing monomer
increases the flame resistance of the high nitrile multipolymer and its
end products.
In the practice of the present invention the polymerization process is
carried out as an emulsion, a solution, a suspension or in continuous
addition bulk. Preferably, the polymerization process is carried out as an
emulsion or a suspension. The present invention can be practiced as a
semibatch or continuous process. The process of the present invention is
not carried out as a batch process which batch process is defined herein
as a process in which all the reactants are charged initially to the
reaction vessel prior to the initiation of polymerization.
Initially, acrylonitrile monomer and olefinically unsaturated monomer(s)
are contacted in an aqueous medium at about 0.1% by weight to about 15% by
weight of the total polymerization reaction media. The initial
multimonomer mixture contains about 50% by weight to about 95% by weight
acrylonitrile monomer and about 5% by weight to about 50% by weight
olefinically unsaturated monomer(s).
The aqueous medium contains water and a suitable surfactant such as an
emulsifier or a dispersing agent. The surfactants and their uses are known
to those skilled in the art.
A molecular weight modifier may be added to the initial multimonomer
mixture in the range of about 0% by weight to about 5% by weight,
preferably about 0.1% by weight to 4% by weight and most preferably about
0.1% by weight to about 3% by weight of the total multimonomer mixture.
The initial multimonomer mixture is placed into a reaction vessel
containing aqueous medium. The reaction vessel with the aqueous medium is
purged with an inert gas, such as nitrogen, argon and the like.
Preferably, but optionally, the inert gas purge is continued throughout
the polymerization reaction. The initial multimonomer mixture is then
heated to a temperature in the range of about 30.degree. C. to about
120.degree. C., preferably about 40.degree. C. to about 100.degree. C. and
most preferably about 50.degree. C. to about 80.degree. C. The temperature
of the polymerization reaction is maintained throughout the process in the
range of about 30.degree. C. to about 120.degree. C., preferably about
40.degree. C. to about 100.degree. C. and most preferably about 50.degree.
C. to about 80.degree. C.
An initiator is added to the heated initial multimonomer mixture to start
the polymerization reaction. The initiator is added generally in the range
of about 0.01% by weight to about 5% by weight of the total multimonomer
mixture.
After the polymerization reaction commences, a multimonomer feed mixture of
acrylonitrile monomer and olefinically unsaturated monomer(s) is
continuously added to the polymerization reaction in the reaction vessel.
The combined weight of the unreacted acrylonitrile monomer and unreacted
olefinically unsaturated monomer(s) present in the polymerizing mixture,
at any time, is not greater than about 15% by weight, preferably not
greater than about 10% by weight, and most preferably not greater than
about 5% by weight of the polymerizing mixture.
The multimonomer feed mixture contains about 50% by weight to about 95% by
weight acrylonitrile monomer, and 5% by weight to about 50% by weight
olefinically unsaturated monomer(s). The molar ratio of the acrylonitrile
monomer and the olefinically unsaturated monomer(s) in the multimonomer
feed mixture, is fixed and constant throughout the polymerization process
resulting in a homogeneous multipolymer. The feed molar ratio of the
acrylonitrile monomer to olefinically unsaturated monomer depends on the
desired acrylonitrile, olefinically unsaturated multipolymer composition.
The multipolymer composition is similar to the composition of the
multimonomer feed mixture.
A molecular weight modifier is optionally added to the polymerization
mixture. Preferably, a molecular weight modifier is employed in the
polymerization mixture. The molecular weight modifier is added
continuously or incrementally to the polymerization mixture. Preferably,
the molecular weight modifier is added continuously to the polymerization
mixture. The molecular weight modifier is preferably added to the
polymerization reaction media in the range of about 0% by weight to about
5% by weight, preferably about 0.1% by weight to about 4% by weight, and
most preferably about 0.1% by weight to about 3% by weight of the total
multimonomer mixture.
The molecular weight modifier includes but is not limited to mercaptans,
alcohols, halogen compounds or any other chain transfer agent known to
those skilled in the art. Mercaptans are the preferred molecular weight
modifier and include mono-mercaptans, multifunctional mercaptans or
combinations thereof. The mercaptans include but are not limited to
C.sub.5 to C.sub.18 alkyl mercaptans whether straight chained, branched,
substituted or unsubstituted, d-limonene dimercaptan, dipentene
dimercaptan and the like. The preferred mercaptans are the C.sub.5 to
C.sub.12 alkyl mercaptans whether straight chained, branched, substituted
or unsubstituted, for example t-dodecyl mercaptan and n-octyl mercaptan.
The molecular weight modifier can be employed singularly or in
combination. The molecular weight modifier can be the same or a different
molecular weight modifier as is employed with the initial multimonomer
mixture.
The molecular weight modifier controls the molecular weight of the
polymerized acrylonitrile olefinically unsaturated multipolymer chain by
terminating the growing chain. The molecular weight modifier useful in the
present invention produces an acrylonitrile, olefinically unsaturated
multipolymer with a molecular weight in the range of about 15,000
molecular weight to about 500,000 molecular weight.
The initiator is added typically as a single solution, continuously or
incrementally, to the polymerization mixture as a separate stream.
Preferably, the initiator is added continuously. The initiator is added at
a rate to maintain the polymerization rate, which rate can be determined
by those skilled in the art. The concentration of the initiator is
generally in the range of about 0.01% by weight to about 5% by weight of
the total multimonomer mixture.
The initiator is any free radical initiator known to those skilled in the
art. The initiator includes but is not limited to azo compounds,
peroxides, hydroperoxides, alkyl peroxides, peroxydicarbonates,
peroxyesters, dialkyl peroxides, persulfates, perphosphates, and the like.
Persulfates are the preferred initiators. The initiator can be employed
singularly or in combination. The initiator can be the same or a different
initiator as is employed to start the polymerization reaction.
The polymerization mixture is continuously or intermittently agitated by
any known method, such as stirring, shaking and the like. Preferably, the
polymerization mixture is continuously agitated.
The reaction is continued until polymerization has proceeded to the desired
extent, generally from about 40% to about 99% conversion and preferably
from about 70% to about 95% conversion.
The polymerization reaction is stopped by cooling; adding an inhibitor;
such as diethyl hydroxylamine, 4-methoxyphenol and the like; discontinuing
the multimonomer feed mixture; and the like. The inhibitors and their use
are known to those skilled in the art.
It will be readily apparent to one skilled in the art that the
acrylonitrile olefinically unsaturated multipolymer may be further
modified by the addition of lubricants, dyes, leaching agents,
plasticizers, pseudoplasticizers, pigments, delustering agents,
stabilizers, static control agents, antioxidants, reinforcing agents such
as fillers and the like. It is understood that any additive possessing the
ability to function in such a manner can be used as long as it does not
have a deleterious effect on the melt characteristics and thermal
stability of the high nitrile multipolymer.
At the conclusion of the polymerization reaction the acrylonitrile
olefinically unsaturated multipolymer is isolated as a solid, slurry or a
latex. Any known technique may be used to isolate the acrylonitrile
olefinically unsaturated multipolymer such as crumb coagulation, spraying
the solution of the multipolymer into a heated and/or evacuated chamber to
remove the water vapors, stripping, filtration, centrifugation and the
like.
The acrylonitrile olefinically unsaturated multipolymer produced by the
process of the instant invention is a high nitrile thermoplastic
multipolymer containing polymerized acrylonitrile monomer and olefinically
unsaturated monomer(s). The multipolymer comprises about 50% by weight to
about 95% by weight polymerized acrylonitrile and about 5% by weight to
about 50% by weight polymerized olefinically unsaturated monomer(s). The
multipolymer product is homogeneous in that the composition and sequencing
of the multipolymer produced is substantially the same throughout the
process.
The acrylonitrile olefinically unsaturated multipolymer is thermally
stable, melt processable without the addition of any solvents and
homogeneous. The multipolymer of the present invention may be further
processed by spinning, molding, extruding and the like without the use of
solvents. The acrylonitrile olefinically unsaturated multipolymer
possesses excellent thermal, physical and mechanical properties, can be
readily oriented and is homogenous with short sequences of polymerized
nitrile monomer units. Further, the acrylonitrile olefinically unsaturated
multipolymer may be utilized in numerous applications such as for use as
fibers, sheets, films, pipes, tubings, molded articles and the like.
SPECIFIC EMBODIMENT
The following examples demonstrate the process and advantages of the
present invention.
Equipment
A 1 or 2 liter circulating hot water jacketed reactor was equipped with a
reflux condenser, a thermocouple/controller, a paddle for agitation, which
paddle was set at about 230 rpm to about 250 rpm, an argon purge tube
(continuous), a monomer feed mixture pump and an ammonium persulfate
initiator feed pump.
Components
The overall polymerization components for the examples were as follows:
______________________________________
Component Grams (gm)
______________________________________
Example 1
Water 1260.0
Rhofac RE-610 12.6
Acrylonitrile (AN) 342.3
.alpha.-Methyl styrene (MS)
77.7
n-Octyl Mercaptan 8.4
Ammonium Persulfate 1.3
Total: 1702.3
Example 2
Water 1320.0
Rhofac RE-610 17.6
Acrylonitrile (AN) 378.4
Methyl Acrylate (MA)
30.8
Methyl Methacrylate (MMA)
30.8
n-Octyl Mercaptan 8.8
Ammonium Persulfate 2.8
Total: 1789.2
Example 3
Water 1320.0
Rhofac RE-610 17.6
Acrylonitrile (AN) 338.8
Methyl Methacrylate (MMA)
101.2
n-Octyl Mercaptan 8.8
Ammonium Persulfate 2.8
Total: 1789.2
Example 4
Water 1200.0
Dowfax 8390 (35% active)
45.7
Acrylonitrile (AN) 340.0
Methyl Acrylate (MA)
60.0
n-Dodecyl Mercaptan 11.2
Ammonium Persulfate 0.8
Total: 1657.7
Example 5
Water 1200.0
Rhofax RE-610 12.0
Acrylonitrile (AN) 344.0
Styrene (ST) 56.0
n-Octyl Mercaptan 9.0
Ammonium Persulfate 2.5
Total: 1623.5
Example 6
Water 750.0
Dowfax 8390 (35% active)
7.5
Acrylonitrile (AN) 212.5
Vinyl Acetate (VA) 37.5
n-Dodecyl Mercaptan 7.0
Ammonium Persulfate 1.6
Total: 1016.1
Example 7
Water 1200.0
Rhofax RE-610 12.0
Acrylonitrile 340.0
Methyl Methacrylate (MMA)
30.0
Vinyl Acetate (VA) 30.0
n-Octyl Mercaptan 8.0
Ammonium Persulfate 2.5
Total 1622.5
______________________________________
The Rhofac RE-610 is available from Rhone-Poulenc. Dowfax is available from
Dow Chemical Co.
Procedure:
The reactor was pre-charged with water and the surfactant which had been
pre-dissolved at about 50.degree. C. with stirring at about 230-250 rpm
(see Table I). The reactor was heated to about 70.degree. C. with
continuous argon purging. The initial monomer charge (see Table II) was
added to the reactor. Ammonium persulfate initiator was added to the
reactor to initiate the polymerization reaction.
The multimonomer feed mixture (see Table III) containing mercaptan was
continuously pumped into the reactor at a constant, fixed weight ratio of
acrylonitrile monomer ("AN") to the olefinically unsaturated monomer ("X")
(see Table VI). Simultaneously, the ammonium persulfate initiator was
pumped into the reactor (See Table IV). Both the multimonomer feed mixture
stream and the initiator stream were fed into the reactor as separate
streams. Total polymerization reaction time was about 4 to about 6 hours.
After the polymerization reaction was completed the resulting multipolymer
emulsion was filtered through a piece of pre-weighed cheesecloth to
collect and separate any coagulum from multipolymer. The coagulum was
bundled in a cheesecloth and rinsed with warm tap water. The cheesecloth
was dried overnight at about 60.degree. C. Then the dried
cheesecloth/coagulum was weighed. The coagulum was about nil to about 3%
by weight multimonomers. The latexes were then coagulated in about 1%
aluminum sulfate aqueous solution at about 75.degree. C. to 85.degree. C.
with continuous stirring. The washed and filtered multipolymer crumb was
dried for about 3 to about 24 hours on a vacuum filtered funnel. The
multipolymer was then dried in a fluidized bed dryer at about 55.degree.
C. for about 3 hours. The acrylonitrile, olefinically unsaturated
multipolymer was then analyzed (See Table V and VI).
TABLE I
______________________________________
Aqueous Precharge
Example
Water Rhofac RE-blu (gm)
Dowfax 8390
______________________________________
1 1160 12.6 0
2 1220 17.6 0
3 1220 17.6 0
4 1100 0 45.7
5 1100 12.0 0
6 677.5 0 20.0
7 1100 12.0 0
______________________________________
TABLE II
__________________________________________________________________________
INITIAL MONOMER CHARGE (gm)
Olefinically
Olefinically
Unsaturated
Unsaturated
Initiator
Acrylonitrile
Monomer
Monomer
Ammonium
Example
Mercaptan
Monomer
X-1 X-2 persuffate (gm)
__________________________________________________________________________
1 2.1 gm n-octyl
21.0 21.0
MS 0 0.71
mercaptan
2 2.2 gm nwyl
37.8 3.1
MMA 3.1 MMA
1.45
mercaptan
3 2.2 gm n-octyl
41.8 2.2
MMA 0 1.45
mercaptan
4 2.8 gm n-
34.0 6.0
MA 0 0.42
dodecyl
mercaptan
5 2.24 gm n-
38.0 2 ST 0 1.32
octyl
mercaptan
6 1.8 gm n-
13.8 11.3
VA 0 0.53
dodecyl
mercaptan
7 2.0 gm n-octyl
34.0 3.0
MA 3.0 MA 1.33
mercaptan
__________________________________________________________________________
TABLE III
__________________________________________________________________________
MULTIMONOMER FEED MIXTURE
X.sub.1
X.sub.2
Total
Mercaptan*
AN Monomer
Monomer
Monomer
Polymermization
Example
(gm) (gm) (gm) (gm) (hrs.)
__________________________________________________________________________
1 6.3 321.3 56.7
MS 0 6
2 6.6 336.6 29.7
MMA 29.7 MA
6
3 6.6 297 99.0
MMA 0 6
4 8.4 306 54 MA 0 4
5 6.76 306 54 ST 0 6
6 5.3 199 26.2
VA 0 5
7 6.0 306 27.0
VA 27.0 MA
6
__________________________________________________________________________
*n-octyl mercaptan was employed in examples 1, 2, 3, 5, and 7.
ndodeceyl mercaptan was employed in examples 4 and 6.
TABLE IV
______________________________________
Aqueous Initiator Feed Mixture
Ammonium Persulfate
Example (gms) Water (gms0
______________________________________
1 0.63 100
2 1.31 100
3 1.31 100
4 0.38 100
5 1.2 100
6 1.1 61
7 1.31 100
______________________________________
TESTING:
Molecular Weight:
The molecular weight (MW) of a multipolymer was determined by Gel
Permeation Chromatography (GPC) in dimethyl formamide solvent and
calibrated with polystyrene standards. This is a known standard method.
The results are presented in Table V.
Glass Transition Temperature:
The glass transition temperature (Tg) was obtained by differential scanning
calorimetry (DSC), A DuPont 1090 instrument was used over a temperature
range from room temperature to 240.degree. C. at a heating rate of about
5.degree. C./minute under an atmosphere of nitrogen The results are
presented in Table V.
NMR Analysis:
Samples for NMR Analysis were prepared using DMSO-D6 as solvent.
Compositions were determined using .sup.1 H spectra and sequence
distributions were determined using .sup.13 C spectra. .sup.1 H spectra
were obtained using a Varian Gemini 300 Spectrometer at 300 MHz and/or a
Varian VXR-400 Spectrometer at 400 MHz. .sup.13 C spectra were obtained
using a Varian Gemini 300 Spectrometer at 75.5 MHz and/or a Varian VXR-400
Spectrometer at 100.7 MHz. The numerical data is presented in Table VI.
Brabender Plasticorder:
The Brabender plasticorder, available from C. W. Brabender Instruments
Inc., South Hackensack, N.J., is a low shear melt mixing device that
measures the torque (meter-grams, m-g) required to melt stir a molten
polymer. The test determines whether a polymer may be melted and processed
employing standard thermoplastic equipment. The Brabender analyses were
run at about 200.degree. C. with torque readings taken at about 5 minute
intervals to about 30 minutes. This method measures polymer degradation as
a function of time, temperature, and physical abrading. The numerical data
is presented in Table V.
TABLE V
__________________________________________________________________________
Polymer Physical Properties
Brabender
Brabender
Brabender
Molecular
Torque Torque Torque
Weight
m-gm, 200.degree. C.
m-gm, 200.degree. C.
m-gm, 200.degree. C.
Example
Tg (.degree.C.)
M.sub.w
10 minutes
20 minutes
30 minutes
__________________________________________________________________________
1 103 50,000
420 420 429
2 81 46,000
653 641 641
3 83 43,000
298 286 298
4 77 62,000
939 996 1115
5 93 43,000
529(220.degree. C.)
550(220.degree. C.)
732(220.degree. C.)
6 90 59,000
900 1329 1836
7 86 48,000
1026 957 992
__________________________________________________________________________
TABLE VI
______________________________________
Polymer Chemical Properties
by .sup.13 C NMR
______________________________________
Composition
Monomer Monomer Polymer
Example Composition Charge Ratio (%)
Analysis (%)
______________________________________
1 AN/MS 81/19 76.4/23.6
2 AN/MMA/MA 85/7.5/7.5 83.2/11.2/5.6
3 AN/MMA 75/25 68.5/31.5
4 AN/MA 85/15 85.7/14.3
5 AN/ST 85/15 84.8/15.2
6 AN/VA 85/15 84.6/15.4
7 AN/MA/VA 85/7.5/7.5 87.4/7.7/4.9
______________________________________
Monomer Sequence
Example
______________________________________
XXX XXA AXA XAX AAX AAA
1 12.9 43.4 43.7 8.2 48.3 43.5
2 BBA ABA CCA ACA XAX AAX AAA
18.7 81.3 7.9 92.1 2.7 14.8 82.5
XXX XXA AXA XAX AAX AAA
3 0 20.8 79.2 0 31.3 68.7
4 7.5 24.6 67.9 4.0 19.6 76.5
5 16.0 59.9 24.0 1.5 13.1 85.5
6 * * * 3.1 20.2 76.7
7 * * * 2.9 18.3 78.8
______________________________________
A = acrylonitrile
B = methyl methacrylate
C = Methyl acrylate
X = olefinically unsaturated monomer
*Not measurable by .sup.13 C NMR
Results:
A very uniform and homogeneous acrylonitrile olefinically unsaturated
multipolymer was produced by the process described herein. The final
conversion to multipolymer was about 90% based on total multimonomers.
The weight average molecular weight of the multipolymer examples were in
the range of about 43,000 to about 62,000.
The Brabender torque data for the examples in the range of about 420 m-gm
to about 1026 m-gm at ten minutes and about 429 m-gm to about 1329 m-gm at
thirty minutes. This demonstrates that the multipolymer is easily melt
processed and is thermally stable. The Brabender torque data is shown in
Tables V.
NMR data demonstrated that the sequencing of the multipolymer was
interdispersed and had a high degree of randomness as shown in Table VI.
Further, the polymer analysis demonstrates that the multipolymer product
ratio is similar to the multimonomer feed ratio.
From the above description and examples of the invention those skilled in
the art will perceive improvement, changes and modification in the
invention. Such improvements, changes and modifications within the skill
of the art are intended to be covered by the appended claims.
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